Modulation of intra-pulmonary TGF-b expression by mycophenolate mofetil in lupus prone MRL/lpr mice

Dermatomyositis: Practical Guidance and Unmet Needs

Dermatomyositis is a heterogeneous idiopathic inflammatory myopathy associated with various cutaneous manifestations and variable presence of myositis, interstitial lung disease, and other visceral organ involvement. An accurate diagnosis of dermatomyositis requires correlating clinical examination findings with serological and histological findings. Familiarity with pathognomonic and common cutaneous manifestations of dermatomyositis, which are highlighted here, can be especially helpful in making an accurate diagnosis. Additionally, evaluating patients for presence of myositis-specific autoantibodies can further support or refute a dermatomyositis diagnosis. When present, myositis-specific autoantibodies can also help guide workups for various dermatomyositis-associated manifestations, as each is associated with relatively distinct clinical characteristics. Evaluating patients for various systemic manifestations often relies on expert opinion recommendations; however, societal guideline statements concerning the evaluation of some manifestations have recently been described. Although malignancy-associated dermatomyositis is a well-accepted subtype, there is limited evidence to support extensive malignancy screening has a favorable benefit-risk ratio in most dermatomyositis patients. However, recent research has uncovered novel associations between dermatomyositis and malignancy, suggesting the possibility of identifying high-risk subsets of dermatomyositis patients in whom malignancy screening may have a high value. Treatment for dermatomyositis has remained largely unchanged over the past several decades. Although many dermatomyositis patients can be effectively treated with current options, either as monotherapy or with combination regimens, there is a need for more targeted and effective DM therapies, in general, and for MDA5(+) dermatomyositis-associated rapidly progressive interstitial lung disease. Fortunately, significant current and emerging research activities evaluating various novel medications for dermatomyositis provide hope for exciting future advances in patients with this intriguing immune-mediated disease.

The emerging role of mycophenolate mofetil in interstitial lung diseases

INTRODUCTION

Mycophenolate mofetil (MMF), initially approved to prevent rejection in solid organ allograft, is now being increasingly used for other conditions. Over the last decade, MMF has emerged as a useful therapy for a variety of immune-mediated diseases.

AREAS COVERED

There has been a growing interest in the clinical use of MMF in the treatment of ILDs due to its versatile anti-inflammatory, immunomodulatory, anti-fibrotic and anti-proliferative properties. In this focussed review, we summarize the available literature using the Pubmed, Science Direct and EMBASE databases published until June 2021 on the efficacy and tolerability of MMF in various ILDs.

EXPERT OPINION

Other than idiopathic pulmonary fibrosis (IPF) and its broader category of progressive fibrosing ILD, there have been no drugs approved by relevant regulatory agencies for the treatment of the multiple other forms of ILD. Though results are limited, immunosuppressants such as MMF have shown promise as an effective and well-tolerated steroid-sparing agent, providing hope that the limited treatment armamentarium for ILDs can be expanded.

Are lupus animal models useful for understanding and developing new therapies for human SLE?

Systemic lupus erythematosus is a systemic autoimmune disease driven by a complex combination of genetic, environmental, and other immunoregulatory factors. The development of targeted therapies is complicated by heterogeneous clinical manifestations, varying organ involvement, and toxicity. Despite advances in understanding the mechanisms contributing to SLE, only one biologic drug, belimumab, is FDA-approved. The identification and development of potential therapies have largely been driven by studies in lupus animal models. Therefore, direct comparison of both the therapeutic and immunological findings in human and murine SLE studies is critical and can reveal important insights into indeed how useful and relevant are murine studies in SLE drug development. Studies involving belimumab, mycophenolate mofetil, abatacept, rituximab, and anti-interferon strategies generally demonstrated analogous findings in the attenuation of SLE manifestations and modulation of select immune cell populations in human and murine SLE. While further basic and translational studies are needed to identify SLE patient subsets likely to respond to particular therapeutic modalities and in dissecting complex mechanisms, we believe that despite some inherent weaknesses SLE mouse models will continue to be integral in developing targeted SLE therapies.

Anti-melanoma differentiation-associated gene 5 (MDA5) dermatomyositis: A concise review with an emphasis on distinctive clinical features

Melanoma differentiation-associated gene 5 (MDA5) is a recently described autoantigen target in a subset of patients with dermatomyositis. Anti-MDA5 dermatomyositis is characterized by a unique mucocutaneous and systemic phenotype that includes cutaneous and oral ulceration, painful palmar papules, alopecia, panniculitis, arthritis, a lower incidence of myositis, and, importantly, an elevated risk of interstitial lung disease with a potentially fatal course. Because the clinical features can differ substantially from those typically observed in cutaneous dermatomyositis, the diagnosis is often overlooked, which might negatively affect patient outcomes. This review aims to familiarize the clinician with the distinctive clinical features of anti-MDA5 dermatomyositis in order to enhance its recognition and to facilitate an appropriate screening and management strategy.

Effectiveness and safety of mycophenolate mofetil in idiopathic pulmonary fibrosis

BACKGROUND

Currently available antifibrotic treatments may slow down disease progression in idiopathic pulmonary fibrosis (IPF), but are associated with potentially significant side effects and are costly. Mycophenolate mofetil (MMF) is well known for its potent immunosuppressive properties and possesses important antiproliferative and antifibrotic effects. The safety and effectiveness of MMF in IPF is unknown.

METHODS

We performed a retrospective multicohort analysis of IPF patients treated with MMF compared to those treated with either ineffective/harmful treatments or no treatment. Longitudinal change in forced vital capacity (FVC) between the groups was analyzed using a mixed model with random intercept and slope allowing for repeated measures within subjects. Categorical change in FVC, median overall survival, and adverse events were also assessed.

RESULTS

Forty-one IPF patients were included: 11 treated with MMF, 20 treated with ineffective/harmful agents (such as prednisone, azathioprine, and/or NAC), and 10 did not receive any specific treatment for their IPF. After one year, there was a trend towards reduced FVC decline in the MMF-treated group (-76.3 mL, -2.4% of predicted) compared to the non-MMF-treated (-165 mL, -8.9% of predicted) and the no-treatment (-239 mL, -11.5% of predicted) groups, respectively. By categorical change, there was a trend towards greater FVC stability in the MMF-treated group (87.5%) compared to the non-MMF-treated (57%) and the no-treatment groups (50%), respectively. MMF-treated IPF patients had a trend towards improved median overall survival (40.3 months) compared to the non-MMF-treated (25.5 months) and the no-treatment (29.3 months) groups, respectively. Treatment-related adverse events were not different between groups; however, very few adverse events were reported overall.

CONCLUSIONS

MMF treatment was associated with potentially clinically important trends toward reduced annual FVC decline (similar to approved antifibrotics), greater FVC stability and improved overall survival in IPF patients. MMF was generally safe, well tolerated, and relatively inexpensive. Future prospective studies of MMF in combination with antifibrotic therapy in IPF are needed.

Tolerogenic probiotics: potential immunoregulators in Systemic Lupus Erythematosus

Probiotics are commensal or nonpathogenic microbes that colonize the gastrointestinal tract and confer beneficial effects on the host through several mechanisms such as competitive exclusion, anti-bacterial effects, and modulation of immune responses. There is growing evidence supporting the immunomodulatory ability of some probiotics. Several experimental and clinical studies have been shown beneficial effect of some probiotic bacteria, particularly Lactobacillus and Bifidobacteria strains, on inflammatory and autoimmune diseases. Systemic lupus erythematosus (SLE) is an autoimmune disease that is mainly characterized by immune intolerance towards self-antigens. Some immunomodulatory probiotics have been found to regulate immune responses via tolerogenic mechanisms. Dendritic and T regulatory (Treg) cells, IL-6, IFN-γ, IL-17, and IL-23 can be considered as the most determinant dysregulated mediators in tolerogenic status. As demonstrated by documented experimental and clinical trials on inflammatory and autoimmune diseases, a number of probiotic bacterial strains can restore tolerance in host through modification of such dysregulated mediators. Since there are limited reports regarding to impact of probiotic supplementation in SLE patients, the preset review was aimed to suggest a number of probiotics bacteria, mainly from Bifidobacteria and Lactobacillus strains that are able to ameliorate immune responses. The aim was followed through literature survey on immunoregulatory probiotics that can restore tolerance and also modulate the important dysregulated pro/anti-inflammatory cytokines contributing to the pathogenesis of SLE.

Mycophenolate mofetil and systemic lupus erythematosus

Mycophenolate mofetil (MMF) is an immunosuppressive agent which provides protection against acute transplant rejection, in patients who undergo kidney, heart and liver transplantation. Recently MMF has been used in various autoimmune conditions, including systemic lupus erythematosus (SLE). In SLE, MMF has been more extensively used in the treatment of proliferative lupus glomerulonephritis (GLN) and following the success in this field, it has also been used to control extra-renal manifestations. However, in the majority of cases MMF was administered to patients with refractory SLE manifestations and, therefore, no definite conclusion could be drawn from these experiences.

In this paper, after a brief description of the mechanisms of action, the pharmacokinetics and metabolism of MMF which are relevant in SLE, and after a short discussion on the utility of performing therapeutic dose monitoring of mycphenolic acid, the experiences with the use of this drug in the different SLE manifestations were summarized and some personal data in patients with GLN were reported. Finally, the hypothetical use of MMF as a preventive strategy against the occurrence of severe manifestations in patients with mild SLE has been put forward and discussed.

Mycophenolate mofetil and animal models

Mycophenolate mofetil (MMF), is the morpholinoethyl ester of mycophenolic acid (MPA). Though initially developed as an anti-rejection treatment, MMF is beginning to find application in more common immune-mediated diseases. MMF has been shown to be effective against transplant-associated vascular disease, lupus and other inflammatory diseases via multiple mechanisms in several animal models. MMF treatment blocks the proliferation of T cells and B cells, attenuates the production of autoreactive IgG and IgM, diminishes complement deposition, and reduces the production of multiple proinflammatory cytokines including TNF-α, IFN-γ, IL-2, IL-3, IL-4, IL-5, IL-6 and IL-12. It also increases production of the anti-inflammatory mediator IL-10. In addition, MMF reduces the infiltration of immune cells into sites of inflammation by interfering with the expression of cell-surface molecules critical for this process, including MHC class II, CD40, CD80, CD86, I-A, and ICAM-1. Additional mechanisms involving mannosylation and N-linked glycosylation of cell-surface molecules are only beginning to be investigated. This article will focus on the contribution of animal models of disease as investigational tools in the development of MMF as an immunomodulatory drug. The use of mice, rats, rabbits, monkeys, baboons and interspecific xenografts will be discussed.

Mycophenolate mofetil as an immunomodulatory silver bullet in atherogenesis?

Atherosclerotic vascular disease is a chronic disorder of the vasculature with a substantial impact on society. Although the availability of statins has represented an unparalleled improvement in the treatment of patients with such cardiovascular disease, even more effective measures are required to reverse this disorder with a continuously growing incidence. The classification of atherosclerosis as an inflammatory disorder has prompted the hypothesis that immunomodulation could comprise a novel anti-atherosclerotic strategy. Mycophenolate mofetil (MMF) has various anti-atherogenic effects on major components of the atherosclerotic plaque such as T-lymphocytes, monocytes/macrophages and the endothelium. MMF can inhibit leukocyte recruitment to the subendothelium and the subsequent reduced activation of leukocytes will translate into attenuation of subendothelial crosstalk between T-cells and macrophages. This cascade of events will interrupt the self-perpetuating pro-inflammatory environment within the arterial wall, the hallmark of atherosclerotic vascular disease.

Roles of pro- and anti-inflammatory cytokines in the pathogenesis of SLE

SLE is an autoimmune inflammatory disease in which various pro- and anti-inflammatory cytokines, including TGF-β, IL-10, BAFF, IL-6, IFN-α, IFN-γ, IL-17, and IL-23, play crucial pathogenic roles. Virtually, all these cytokines can be generated by both innate and adaptive immune cells and exert different effects depending on specific local microenvironment. They can also interact with each other, forming a complex network to maintain delicate immune homeostasis. In this paper, we elaborate on the abnormal secretion and functions of these cytokines in SLE, analyze their potential pathogenic roles, and probe into the possibility of them being utilized as targets for therapy.

Effect of mycophenolate sodium in scleroderma-related interstitial lung disease

This study aims to determine the effectiveness of mycophenolate sodium (MS) in patients with scleroderma (SSc)-related interstitial lung disease (ILD). In a prospective observational study, we evaluated 14 consecutive SSc-ILD patients who were treated with MS for 12 months. The effect of MS on lung function was examined by using longitudinal data analytic methods. Wilcoxon rank-sum tests were used to examine the forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) by pulmonary function testing. As a group, the median values for FVC, FEV1 and DLCO did not change significantly after 12 months of MS therapy and fulfilled the definition of stable disease by the American Thoracic Society. Individually, after 12 months of treatment, 6 out of 14 patients showed a pulmonary improvement defined as an increase of more than 10% in FVC, and 5 out of 14 patients remained stable. By contrast, the median FVC had declined a non-significant 7.2% from the previous 12 months before MS initiation. No significant drug adverse effects were registered. These prospective data suggest that MS is a safe and well-tolerated therapy for SSc-ILD patients, and it is capable of preventing functional pulmonary deterioration.

In rat renal fibroblasts, mycophenolic acid inhibits proliferation and production of the chemokine CCL2, stimulated by tumour necrosis factor-alpha

BACKGROUND AND PURPOSE

Renal fibroblasts play a pivotal role in the development of tubulointerstitial fibrosis, a condition highly predictive of progression towards end-stage renal disease. The present study investigated the anti-mitogenic and anti-inflammatory effects of an inhibitor of inosine monophosphate dehydrogenase, mycophenolic acid (MPA) and the mechanisms underlying its action in normal rat kidney fibroblasts (49F cells).

EXPERIMENTAL APPROACH

Proliferation of 49F cells was studied by tetrazole 3-(4, 5-dimethylthiazol-2-yl-)-2,5-diphenyltetrazolium bromide (MTT) test, bromodeoxyuridine incorporation and flow cytometry. The cyclins, tumour suppressor genes and phospho-mitogen-activated protein kinases (MAPKs) were semiquantified by immunoblotting. Apoptosis was measured by quantifying the fragmented DNA and the activity of caspase 3. The monocyte chemokine CCL2 was measured by ELISA. The mRNA expression of CCL2 was measured by real-time PCR.

KEY RESULTS

Mycophenolic acid dose-dependently inhibited steady-state proliferation of 49F cells by up-regulation of p21, p27 and p53, in association with a decrease in cyclins D2 and E. Treatment with MPA also triggered apoptosis of 49F cells by activating the caspase 3 cascade. Furthermore, MPA attenuated tumour necrosis factor-alpha-induced CCL2 expression through down-regulation of p38 MAPK, but not that of ERK1/2 or JNK.

CONCLUSIONS AND IMPLICATIONS

The anti-mitogenic and anti-inflammatory effects of MPA were mediated by up-regulation of cell cycle inhibitors and pro-apoptotic signals, and by suppression of p38 MAPK pathway respectively. This dual effect of MPA may form the rationale for animal or clinical trials for the treatment of fibrotic renal diseases.

Inhibition of inosine monophosphate dehydrogenase reduces adipogenesis and diet-induced obesity

We previously described a putative role for inosine monophosphate dehydrogenase (IMPDH), a rate-limiting enzyme in de novo guanine nucleotide biosynthesis, in lipid accumulation. Here we present data which demonstrate that IMPDH activity is required for differentiation of preadipocytes into mature, lipid-laden adipocytes and maintenance of adipose tissue mass. In 3T3-L1 preadipocytes inhibition of IMPDH with mycophenolic acid (MPA) reduced intracellular GTP levels by 60% (p<0.05) and blocked adipogenesis (p<0.05). Co-treatment with guanosine, a substrate in the salvage pathway of nucleotide biosynthesis, restored GTP levels and adipogenesis demonstrating the specificity of these effects. Treatment of diet-induced obese mice with mycophenolate mofetil (MMF), the prodrug of MPA, for 28 days did not affect food intake or lean body mass but reduced body fat content (by 36%, p=0.002) and adipocyte size (p=0.03) and number. These data suggest that inhibition of IMPDH may represent a novel strategy to reduce adipose tissue mass.

Effect of mycophenolate mofetil on pulmonary function in scleroderma-associated interstitial lung disease

OBJECTIVE

We sought to determine the effectiveness of mycophenolate mofetil (MMF) in scleroderma- associated interstitial lung disease (SSc-ILD).

METHODS

We retrospectively identified patients who met criteria for systemic sclerosis, had evidence of SSc-ILD on chest CT, received > 1 g/d of MMF for >or= 6 months, and had pulmonary function data available. Vital capacity (VC) and diffusion capacity of the lung for carbon monoxide (Dlco) at treatment onset were compared with VC and Dlco values 12 months before and 12 months after treatment onset. Twelve-month values were imputed from regression lines generated using all VC and Dlco measurements made in the 24-month period either prior to or following treatment onset.

RESULTS

Among 13 patients who met inclusion criteria, MMF was associated with a significant improvement in VC (mean, + 159 mL; confidence interval [CI], + 30 to + 289 mL; and + 4% of the predicted normal value; CI, + 2 to + 7%) after 12 months of treatment. In contrast, patients had a significant decrease in VC (mean, - 239 mL; CI, - 477 to - 0.5 mL; and - 5% of the predicted normal value; CI, - 11 to - 0.3%) in the 12 months prior to MMF treatment. Dlco did not change significantly during MMF treatment (mean, + 1% of the predicted normal value; CI, - 2 to + 5%) but decreased significantly in the 12 months prior to treatment (mean, - 5% of the predicted normal value; CI, - 10 to - 1%).

CONCLUSION

These retrospective data suggest MMF improves VC in patients with SSc-ILD.

Mycophenolate mofetil: What is its place in the treatment of autoimmune rheumatic diseases?

Mycophenolate mofetil (MMF) is a new immunosuppressant recently introduced in the treatment of autoimmune conditions. The greatest experience with the use of MMF has been achieved in the treatment of proliferative lupus glomerulonephritis. However, MMF has also been used to control SLE extra-renal manifestations as well as other autoimmune rheumatic diseases such as idiopathic inflammatory arthropathies, inflammatory myopathies, systemic sclerosis, and systemic vasculitis. MMF seems to be well tolerated and effective and could be considered a useful alternative to standard immunosuppressants for the treatment of autoimmune rheumatic disorders. However, further studies are needed in order to determine its real place in the treatment of these conditions. In this paper, the use of MMF in different autoimmune rheumatic diseases is reviewed and discussed.

Transforming growth factor-beta: recent advances on its role in immune tolerance

Transforming growth factor-beta (TGF-beta) is a key regulator of immune tolerance. In this paper, we will focus on T cells and natural killer (NK) cells, which are directly regulated by TGF-beta in vivo. TGF-beta controls T-cell activation and differentiation, and is involved in the suppressive function and generation of regulatory T cells. Recently, TGF-beta has also been shown to directly inhibit NK cell activity. These studies demonstrate that TGF-beta utilizes multiple mechanisms to ensure immune tolerance, which is critical in a variety of autoimmune and inflammatory disorders. We will also discuss recent advances on the role of TGF-beta in immune-mediated diabetes, inflammatory bowel disease, arthritis, and systemic lupus erythematosus.